Protecting elementary stream content

Abstract

Protecting elementary stream media content is described. In one aspect, Media Access Units (MAUs) of elementary stream content are identified. Each MAU includes one or more data segments representing a single video or audio frame. Encryption boundaries are selected for each MAU. The encryption boundaries are based on one or more data segments associated with the respective MAU. Portions of each MAU are encrypted based on corresponding encryption boundaries. Each MAU is mapped to a MAU Payload Format. The MAU Payload Format allows a media consumer to process each elementary stream associated with the elementary stream content independent of any different elementary stream. The MAU Payload Format also allows a media consumer to process each MAU in an elementary stream independent of any other MAU.

1 . A computer-implemented method comprising: 
 identifying Media Access Units (MAUs) of elementary stream content;    for each MAU of the MAUs, the MAU comprising one or more data segments representing a single video or audio frame: 
 selecting encryption boundaries based on the one or more data segments for protection of the single video or audio frame and associated headers; and  
 protecting the MAU as follows: 
 encrypting portions of the MAU based on the encryption boundaries;  
 mapping the MAU to a MAU Payload Format; and  
 wherein the MAU Payload Format provides for processing of the elementary stream independent of any different one of the elementary streams, and provides for processing of the MAU independent of any other MAU.  
 
   
   
   
       2 . The method of  claim 1 , wherein the elementary stream content is carried by a transport stream, and wherein protecting further comprises common scrambling the transport stream such that respective ones of data segments that comprise a MAU of the MAUs are either completely encrypted or completely unencrypted.  
   
   
       3 . The method of  claim 1 , wherein protecting further comprises encrypting separate ones of the one or more data segments with Advanced Encryption Standard in Counter Mode.  
   
   
       4 . The method of  claim 1 , wherein a portion of the MAU is left in the clear.  
   
   
       5 . The method of  claim 1 , wherein mapping the MAU further comprises fragmenting the MAU across multiple transport protocol payloads.  
   
   
       6 . The method of  claim 1 , wherein mapping the MAU further comprises associating multiple payloads for the MAU in a single transport protocol packet.  
   
   
       7 . The method of  claim 1 , further comprising: 
 associating multiple payloads for the MAU in a single transport protocol packet; and    wherein two or more of the multiple payloads have different respective encryption parameters.    
   
   
       8 . The method of  claim 1 , wherein the MAU Payload Format comprises packet specific information associated with all MAUs in a transport protocol packet.  
   
   
       9 . The method of  claim 1 , wherein the MAU Payload Format comprises: 
 a MAU properties section for describing a particular MAU; and    if the MAU is fragmented, the properties section including information to allow a receiver to parse the MAU when a fragmented portion of the MAU is lost.    
   
   
       10 . The method of  claim 1 , wherein the MAU Payload Format comprises a MAU timing section to provide information about timestamps associated with the MAU.  
   
   
       11 . The method of  claim 10 , wherein the information comprises a Normal Play Time (NPT) timeline associated with the MAU, the NPT for assisting specification, by a receiver, a position to seek to within a presentation.  
   
   
       12 . The method of  claim 10 , wherein the information comprises a presentation time indicating when the receiver is to present content of the MAU.  
   
   
       13 . The method of  12 , wherein the presentation time increments at a real-time rate to allow a decoder to decode the MAU without knowing that trick play is used.  
   
   
       14 . The method of  claim 1 , wherein protecting further comprises: 
 analyzing a transport stream to determine portions of the transport stream that are to pass unencrypted;    wherein protecting further comprises preparing the transport stream for processing that bypasses commonly scrambled portions of the transport stream.    
   
   
       15 . A computer-implemented method comprising: 
 receiving elementary streams, each elementary stream (ES) being represented with multiple Media Access Units (MAUs), each MAU corresponding to a single frame of video or audio of the ES, each elementary stream being mapped to a transport protocol that encapsulates a MAU Payload Format (MPF); and    processing the transport stream, the MPF allowing each ES to be processed independent of any other ES, and each MAU to be processed independent of any other MAU.    
   
   
       16 . The method of  claim 15 , wherein the transport protocol is Real-Time Transport Protocol (RTP).  
   
   
       17 . The method of  claim 15 , wherein a portion of a MAU of the MAUs is left in the clear.  
   
   
       18 . The method of  claim 15 , wherein a MAU of the MAUs is fragmented across multiple transport protocol payloads, or wherein multiple payloads for the MAU are in a single transport protocol packet.  
   
   
       19 . The method of  claim 18 , wherein two or more of the multiple payloads have different respective encryption parameters.  
   
   
       20 . A computing device comprising: 
 identifying means to identify Media Access Units (MAUs) of elementary stream content;    for each MAU of the MAUs, the MAU comprising one or more data segments representing a single video or audio frame: 
 selecting means to select encryption boundaries based on the one or more data segments for protection of the single video or audio frame and associated headers; and  
 protecting means to protect the MAU as follows: 
 encrypting means to encrypt portions of the MAU based on the encryption boundaries;  
 mapping means to map the MAU to a MAU Payload Format; and  
 wherein the MAU Payload Format provides for processing of the elementary stream independent of any different one of the elementary streams, and provides for processing of the MAU independent of any other MAU.